Many people are unsure about the different types of foam and wonder whether to have open-cell or closed-cell foam installed. Open-cell foam is full of cells that aren’t completely encapsulated. In other words, the cells are deliberately left open. This makes the foam a softer, more flexible material.
Closed-cell foam is made up of cells that are, as the name suggests, completely closed. The cells are pressed together, so air and moisture are unable to get inside the foam. Because of this, closed cell foam is much more rigid and stable than open cell foam. Closed-cell foam is much denser than open-cell foam. Most open-cell foam has a density of about .5 pounds per cubic foot. Closed-cell foam can be over three times that, with a density of 1.75 pounds per cubic foot or more, making it a much more efficient insulator.
Closed-cell spray foam insulates and air seals wherever it is applied. Air sealing the building envelope with sprayed-in foam insulation also helps address moisture ingress to reduce the risk of mold and mildew growth as well as the formation of ice dams in colder climate zones during the winter months. When you compare foam insulation with traditional fiberglass insulation and cellulose insulation, sprayed insulation minimizes air infiltration, it assists in limiting moisture vapor from entering and escaping the home, which in turn reduces the load on heating and cooling systems.